What percentage of oxygen carried in blood is dissolved in the water of plasma and cells?

Oxygen is carried in the blood in two primary forms: bound to hemoglobin within red blood cells and dissolved in the plasma. Of the total oxygen content in the blood, approximately 3% is dissolved in plasma and the cells.

This value stems from the solubility of oxygen in the liquid portion of the blood, which is relatively low. Although the majority of oxygen is transported attached to hemoglobin, the small amount that is dissolved plays a critical role in maintaining the partial pressure of oxygen and is essential for the diffusion of oxygen from the blood into tissues.

Understanding the proportion of oxygen that is dissolved in plasma helps clarify its availability for cellular metabolism, especially in cases where hemoglobin saturation may be compromised.